Cough-assist systems with humidifier bypass

ABSTRACT

The present technology relates generally to cough-assist devices with humidified cough assistance. In one example, a system includes a cough-assist device having a first phase configured to provide insufflating gas to a patient circuit and a second phase configured to draw exsufflating gas from the patient circuit. A humidifier is disposed between the cough-assist device and a distal end of the patient circuit, the humidifier including a chamber configured to contain heated water and fluidically coupled to the cough-assist device and the patient circuit. The system further includes a bypass configured to (a) direct insufflating gas from the cough-assist device through a first route to the patient circuit such that the insufflating gas is humidified in the chamber, and (b) route exsufflating gas from the patient circuit through a second route to the cough-assist device such that the exsufflating gas bypasses the chamber.

CROSS-CITED TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 15/188,722, filed Jun. 21, 2016, now pending, which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology is generally related to humidifiers forventilation and cough-assist systems.

BACKGROUND

Mechanical ventilators are used to assist with breathing. Conventionalventilators typically drive inspiratory gases including oxygen into thepatient's lungs. Many patients who use a ventilator also need othertypes of assistance related to treating and maintaining their airwaysand lungs, such as cough assistance. Currently, to receive coughassistance, a patient must be disconnected from the mechanicalventilator and connected to a separate cough-assist device. After coughassistance is performed, the patient must be disconnected from thecough-assist device and reconnected to the mechanical ventilator. Often,the patient airway is also suctioned after the patient has beendisconnected from the cough-assist device and reconnected to themechanical ventilator to remove remaining secretions in the patientairway after the cough assistance. Because this process may be tedious,it is often not performed in a manner that is most advantageous to thepatient.

Thus, a need exists for ventilators to provide additional functionalitybeyond delivering inspiratory gases into the patient's lungs, such ascough assistance and humidification. The present technology providesthese and other advantages as will be apparent from the followingdetailed description and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a system that includes aventilator for use by a human patient.

FIG. 2A is a schematic diagram illustrating components of a ventilatorassembly of the ventilator of FIG. 1 with a cough-assist valve of theventilator assembly depicted in a first configuration.

FIG. 2B is a schematic diagram illustrating the cough-assist valve ofthe ventilator assembly in a second configuration.

FIG. 3 illustrates a ventilation system including a ventilator withintegrated cough-assist functionality, a patient circuit, a humidifier,and a humidifier bypass system.

FIGS. 4A-4D illustrate various views of a humidifier bypass system.

FIGS. 5A and 5B illustrate cross-sectional views of another embodimentof a humidifier bypass system.

DETAILED DESCRIPTION

Patients on ventilators often need humidification of both theinspiratory gas provided to the patient and insufflation gas forassisted cough therapy (also referred to as mechanicalinsufflation-exsufflation). Equipping a ventilator with cough-assistancecapabilities eliminates the need to change the patient circuit totransition between ventilation and cough therapy. However, the presentinventors have noted that the high exsufflation flows during coughassistance that pass through the humidifier chamber cause water totravel back to the ventilator. To alleviate this problem, the presenttechnology is directed to a humidifier bypass that permits insufflatinggas to pass through a humidifier chamber to the patient and routesexsufflating gas back to the ventilator without passing through thehumidifier chamber.

The purpose of the ventilator bypass is to redirect the exsufflationflow around the humidifier chamber to prevent the exsufflation flow fromblowing water in the chamber back to the ventilator. The bypass can be apassive accessory that connects to standard commercially availablehumidifier chambers. The bypass can remain in line between theventilator and the patient following cough therapy. When ventilationresumes, the inspired gas is delivered through the humidifier chamber asif the bypass were not present.

In addition, the bypass may also be used by ventilator patients withstandalone cough-assist machines. Typically, the patient circuit isdisconnected at the patient to perform cough therapy. Dedicated patienttubing on the cough machine is then connected to the patient. Withinvasive ventilation, patients can experience discomfort whenmanipulating tubing so close to the tracheostomy site and there is somerisk of accidental decannulation. And, in this scenario, humidified gasis no longer delivered to the patient until ventilation resumes and thehumidifier is back in line. Humidifier bypass systems in accordance withembodiments of the present technology enable the patient circuit to bedisconnected anywhere between the ventilator and humidifier rather thandisconnecting at the patient. Humidified gas is accordingly deliveredduring insufflation, but the bypass prevents ingress of water from thehumidifier into the cough-assist machine during exsufflation.

Further specific details of several embodiments of the presenttechnology are described below with reference to FIGS. 1-5B. Althoughmany of the embodiments are described below with respect to devices,systems, and methods for ventilation with humidified cough assistance,other embodiments are within the scope of the present technology.Additionally, other embodiments of the present technology can havedifferent configurations, components, and/or procedures than thosedescribed herein. For example, other embodiments can include additionalelements and features beyond those described herein, or otherembodiments may not include several of the elements and features shownand described herein.

For ease of reference, throughout this disclosure identical referencenumbers are used to identify similar or analogous components orfeatures, but components identified by the same reference number are notnecessarily identical. Indeed, in many examples described herein, theidentically numbered parts are distinct in structure and/or function.

FIG. 1 is a block diagram illustrating a system 10 that includes aventilator 100 with integrated humidified cough assistance in accordancewith the embodiment of the present technology. Several general aspectsof the system 10 will be described initially to provide an understandingof the components related to embodiments of the humidified bypassdevices of the present technology. The ventilator 100 may be configuredto provide both traditional volume-controlled ventilation andpressure-controlled ventilation. The ventilator 100 has an optionalmulti-lumen tube connection 103, a main ventilator connection 104, and apatient oxygen outlet 105. The system 100 also has a patient connection106 (e.g., a tracheal tube, a nasal mask, a mouthpiece, and the like)and a patient circuit 110 that fluidically couples the patientconnection 106 to the main ventilator connection 104 and/or the patientoxygen outlet 105.

The patient circuit 110 may be an active patient circuit or a passivepatient circuit. Optionally, when the patient circuit 110 is an activepatient circuit, the patient circuit 110 may include one or more ports111 configured to be connected to the optional multi-lumen tubeconnection 103. The port(s) 111 allow one or more pressure signals 109to flow between the optional multi-lumen tube connection 103 and thepatient circuit 110. The pressure signals 109 may be gas(es) obtainedfrom a fluid (and/or gas) source for which a pressure is to be measured.The gas(es) obtained are at the same pressure as the fluid (and/or gas)source.

The system 100 further includes humidifier 141 in line with the patientcircuit 110 and the main ventilator connection 104. In some embodiments,the patient circuit 110 includes a tube or conduit that extends betweenthe humidifier 141 and the main ventilator connection 104 in addition toa tube or conduit that extends between the humidifier 141 and thepatient connection 106. The system 100, or more specifically thehumidifier 141, can be equipped with a bypass 142 as described in moredetail below.

The main ventilator connection 104 is configured to provide gases 112that include air 114 optionally mixed with oxygen. While identified asbeing “air,” those of ordinary skill in the art appreciate that the air114 may include ambient air or pressurized air obtained from any sourceexternal to the ventilator 100. The gases 112 may be inspiratory gasesfor the inspiratory phase of a breath or insufflation gases for theinsufflation phase of cough assistance. The main ventilator connection104 is configured to receive gases 113, which may include exsufflationgases exhaled by the patient 102 during an exsufflation phase of coughassistance.

The air 114 is received by the ventilator 100 via a patient air intake116. Oxygen that is optionally mixed with the air 114 may be generatedinternally by the ventilator 100 and/or received from an optional lowpressure oxygen source 118 (e.g., an oxygen concentrator), and/or anoptional high pressure oxygen source 120. When the oxygen is generatedinternally, the ventilator 100 may output exhaust gases (e.g.,nitrogen-rich gas 122) via an outlet vent 124. Optionally, theventilator 100 may include a low pressure oxygen inlet 126 configured tobe coupled to the optional low pressure oxygen source 118 and receiveoptional low pressure oxygen 128 therefrom. The ventilator 100 mayinclude an optional high pressure oxygen inlet 130 configured to becoupled to the optional high pressure oxygen source 120 and receiveoptional high pressure oxygen 132 therefrom.

The patient oxygen outlet 105 is configured to provide doses or pulsesof oxygen 140 to the patient connection 106 via the patient circuit 110that are synchronized with the patient's breathing. Unlike the gases 112provided by the main ventilator connection 104, the pulses of oxygen 140do not include the air 114.

The gases 112 and/or the pulses of oxygen 140 delivered to thehumidifier 141 and the patient circuit 110 are conducted thereby asinspiratory or insufflation gases 108 to the patient connection 106,which at least in part conducts those gases into the patient's lung(s)143. Whenever the patient exhales during the exhalation phase of abreath or exsufflates during an exsufflation phase of cough assistance,exhaled gases 107 enter the patient circuit 110 via the patientconnection 106. Thus, the patient circuit 110 may contain one or more ofthe following gases: the gases 112 provided by the ventilator 100, thepulses of oxygen 140, and the exhaled gases 107. For ease ofillustration, the gases inside the patient circuit 110 will be referredto hereafter as “patient gases.”

The ventilator 100 can optionally include a suction connection 150configured to be coupled to an optional suction assembly 152. Theventilator 100 may provide suction 154 to the optional suction assembly152 via the optional suction connection 150. The suction assembly 152may be configured to be connected to the patient connection 106, asuction catheter (not shown) positionable inside the patient connection106, and/or a drain (not shown).

The ventilator 100 can additionally include an optional nebulizerconnection 160 configured to be coupled to an optional nebulizerassembly 162. The ventilator 100 may provide gases 164 (e.g., the air114) to the optional nebulizer assembly 162 via the optional nebulizerconnection 160. The optional nebulizer assembly 162 may be configured tobe connected to the patient circuit 110. However, this is not arequirement. Optionally, the ventilator 100 may include an outlet port166 through which exhaust 167 may exit from the ventilator 100.

The ventilator 100 may be configured to be portable and powered by aninternal battery (not shown) and/or an external power source (not shown)such as a conventional wall outlet. The ventilator 100 further includesa ventilation assembly 190, a user interface 170, an oxygen assembly172, a control system 174, and conventional monitoring and alarm systems176. The control system 174 receives input information 196 (e.g.,settings, parameter values, and the like) from the user interface 170,and provides output information 198 (e.g., performance information,status information, and the like) to the user interface 170. The userinterface 170 is configured to receive input from a user (e.g., acaregiver, a clinician, and the like associated with a patient 102) andprovide that input to the control system 174 in the input information196. The user interface 170 is also configured to display the outputinformation 198 to the user.

The ventilation assembly 190 may receive one or more control signals 192from the control system 174, and the ventilation assembly 190 mayprovide one or more data signals 194 to the control system 174. Theventilation assembly 190 may also receive the pressure signals 109 fromthe patient circuit 110 via the multi-lumen connection 103. The oxygenassembly 172 may receive one or more control signals 178 from thecontrol system 174, and the oxygen assembly 172 may provide one or moredata signals 180 to the control system 174. The control signals 192 and178 and the data signals 194 and 180 may be used by the control system174 to monitor and/or control internal operations of the ventilator 100.

FIGS. 2A and 2B are schematic diagrams illustrating an embodiment of theventilation assembly 190, the humidifier 141, and a bypass system 242.Referring to FIGS. 2A and 2B, the ventilation assembly 190 includes acough-assist valve 204, an accumulator 202 and an internal bacteriafilter 230. The cough-assist valve 204 is connected to (a) theaccumulator 202 by a conduit or flow line 214, (b) the outlet port 166by a conduit or flow line 215, and (c) the main ventilator connection104 by a conduit or flow line 273. FIG. 2A depicts the cough-assistvalve 204 in a first configuration for normal breathing and theinsufflation phase of cough assistance, and FIG. 2B depicts thecough-assist valve 204 in a second configuration for the exsufflationphase of cough assistance.

Referring to FIG. 2A, in the first configuration, the cough-assist valve204 receives a gas 252 from the accumulator 202 (via the flow line 214),and outputs the gas 252 to the main ventilator connection 104 (via theflow line 273). The gas 252 flowing through both the blower 222 and thecough-assist valve 204 during the inspiratory phase of a breath or theinsufflation phase of a cough-assist maneuver performed by theventilator 100 (see FIG. 1). During normal breathing/ventilation and theinsufflation phase of cough assistance, the cough-assist valve 204remains in the first configuration. Typical pressure ranges used tosupport normal breathing and ventilation can be from about 10-40 cm H₂Oduring inspiration and from about 0-10 cm H₂O during expiration. Duringcough assistance, the cough-assist valve 204 is in the firstconfiguration (FIG. 2A) during the insufflation phase and the secondconfiguration (FIG. 2B) during the exsufflation phase. Typical pressureranges used provide cough-assist functionality are generally higher thanfor normal breathing/ventilation, such as from about 30-70 cm H₂O duringinsufflation and from about negative 30-70 cm H₂O during exsufflation.

The cough-assist valve 204 has a valve-to-blower outlet 206, ablower-to-valve inlet 208, an air intake 210, an exhaust outlet 212, andan aperture 213. The aperture 213 is connected to the main ventilatorconnection 104 by the flow line 273. As shown in FIG. 2A, when thecough-assist valve 204 is in the first configuration, the air intake 210is in fluid communication with the valve-to-blower outlet 206, and theblower-to-valve inlet 208 is in fluid communication with the aperture213. Further, the exhaust outlet 212 is closed such that both thevalve-to-blower outlet 206 and the air intake 210 are in fluidcommunication with the aperture 213 via only the blower 222. Thus, thegas 252 may flow into the air intake 210, through a portion of thecough-assist valve 204 to the valve-to-blower outlet 206, and into theblower 222. The gas 252 exiting the blower 222 flows into theblower-to-valve inlet 208, through another portion of the cough-assistvalve 204, and into the aperture 213. The aperture 213 is connected tothe flow line 273, which conducts the gas 252 to the main ventilatorconnection 104.

During inspiration or insufflation, the gas 252 passes through the mainventilator connection 104, across the bacterial filter 230 and to thebypass system 242. In the embodiment shown in FIG. 2A, the bypass system242 has a first valve 244 coupled to the humidifier 141 and a secondvalve 246. During normal breathing/ventilation and insufflation, the gas252 flows through a first valve 244 and into the humidifier 141 where itis humidified. The gas 252 then is passed through the output of thebypass system 242 and to the patient circuit 110. The second valve 246of the bypass system 242 prevents the gas 252 from passing directly tothe patient circuit 110 without first going through the humidifier 141.The operation of the bypass system 242 is described in more detail belowwith respect to FIGS. 3-5B.

Referring to FIG. 2B, in the second configuration, the cough-assistvalve 204 receives exsufflation gases 253 via the flow line 273 andoutputs the exsufflation gases 253 (as the exhaust 167) to the outletport 166 via the flow line 215. The exsufflation gases 253 flow throughboth the blower 222 and the cough-assist valve 204 during anexsufflation phase of cough assistance performed by the ventilator 100(see FIG. 1).

As shown in FIG. 2B, when the cough-assist valve 204 is in the secondconfiguration, the air intake 210 is closed, and the blower-to-valveinlet 208 and the exhaust outlet 212 are in fluid communication with theaperture 213 only via the blower 222. Further, the aperture 213 is influid communication with the valve-to-blower outlet 206, and theblower-to-valve inlet 208 is in fluid communication with the exhaustoutlet 212. Thus, the exsufflation gases 253 flow into the aperture 213,across a portion of the cough-assist valve 204, to the valve-to-bloweroutlet 206, and into the blower 222. The exsufflation gas 253 exitingthe blower 222 flows into the blower-to-valve inlet 208, through aportion of the cough-assist valve 204, and exits the cough-assist valve204 though the exhaust outlet 212. The exhaust outlet 212 is connectedto the flow line 215, which conducts the exsufflation gas 253 to theoutlet port 166.

During exsufflation, the gas 253 passes through the patient circuit 110,through the second valve 246 of the bypass system 242, and across thebacterial filter 230 before reaching the main ventilator connection 104.The second valve 246 of the bypass system 242 permits the gas 253 topass to the main ventilator connection 104, while the first valve 244 ofthe bypass system 242 prevents the gas 253 from passing back through thehumidifier 141. For example, the first valve 244 closes duringexsufflation flow to prohibit the gas 253 from passing back through thehumidifier 141 to the main ventilator connection 144. As a result, thehigh velocity exsufflation gas 253 cannot entrain liquid from thehumidifier 141 into the flow of gas 253 back into the ventilator 100.The operation of the bypass system 242 is described in more detail belowwith respect to FIGS. 3-5B.

FIG. 3 illustrates a system 300 including the ventilator 100 withintegrated cough-assist functionality that is coupled to a patientcircuit 110 and a humidifier 141 equipped with an embodiment of thebypass system 242. As illustrated, this embodiment of the humidifier 141and the bypass system 242 are in line with the patient circuit 110. Thepatient circuit 110 includes a first tube 301 connected to the bacterialfilter 230 and one side of the bypass system 242, and a second tube 303connected to another side of the bypass system 242. A distal end 305 ofthe second tube 303 can be connected to the patient connection 106 (FIG.1).

The humidifier 141 includes a base 307 having an integrated heater and achamber 309 configured to retain water. In operation, the base 307 heatsthe water in the chamber 309 to produce water vapor. As a result,inspiration and insufflation gases passing through the chamber 309 arehumidified before being delivered to the patient.

The bypass system 242 is in fluid communication with the chamber 309 aswell as the first tube 301 and the second tube 303 of the patientcircuit 110. In particular, the bypass system 242 includes a firstconduit 311 that extends between the chamber 309 of the humidifier 141and the first tube 301 of the patient circuit 110. The bypass system 242additionally includes a second conduit 313 that extends between thechamber 309 of the humidifier 141 and the second tube 303 of the patientcircuit 110. The bypass system 242 can also include a bridge 315 that isfluidically coupled to and extends between the first conduit 311 and thesecond conduit 313 at a position spaced apart from the chamber 309.

The first valve 244 is disposed in the first conduit 311 in a positionbelow the intersection of the bridge 315 and the first conduit 311. Thefirst valve 244 can be a one-way valve configured to open when thepressure is higher in the first tube 301 than the chamber 309, but closewhen the pressure in the chamber 309 is higher than in the first tube301. As such, during inspiration or insufflation, gas flows from theventilator 100, from the first tube 301 of the patient circuit 110through the first conduit 311 and through the first valve 244 into thechamber 309 of the humidifier 141. However, during exhalation orexsufflation, gas is prevented from flowing back through the chamber 309and up the first conduit 311.

The second valve 246 is disposed in the bridge 315 of the bypass system242. The second valve 246 can be a one-way valve configured to opentowards the first conduit 311 such that, during exsufflation, gas fromthe patient flows from the second tube 303 of the patient circuit 110through the second conduit 313, through the bridge 315, and through thesecond valve 246 towards the ventilator 100. Thus, the opposite one-waydirections and the positions of the first and second valves 244 and 246direct the high-velocity exsufflation gas flow to the ventilator 100without passing through the humidifier 141.

The first and second valves 244, 246 can be many different types ofvalves. For example, one or both of the valves 244, 246 can be ballcheck valves, diaphragm check valves, leaf valves, swing check valves,tilting disc check valves, clapper valves, or any other suitable valvethat allows flow in one direction while disallowing flow in the oppositedirection. The first and second valves 244, 246 can be passive valvesconfigured to open in the presence of flow in one direction without theneed for actuation. In other embodiments, one or both of the valves canbe active valves that are electronically controlled to open or close inresponse to signals communicated from a controller (see FIG. 5).

The system 300 provides a first flowpath 317 through the bypass system242. The first flowpath 317 receives gas flowing from the ventilator 100through the first tube 301 of the patient circuit 110 and into the firstconduit of the bypass system 242. The first valve 244 opens in thepresence of gas flowing in the direction of the first flowpath 317 whilethe second valve 246 is closed. The first flowpath 317 thereforecontinues through the first valve 244, through the chamber 309 of thehumidifier 141, and into the second conduit 313 of the bypass system242. The first flowpath 317 delivers gas into the second tube 303 of thepatient circuit 110 where it then passes through the distal end 305 ofthe patient circuit 110 and to the patient. In this first flowpath 317,the gases (e.g., gases provided by the ventilator 100 either inbreathing assistance (inspiration) or cough-assistance (insufflation)mode) are humidified before reaching the distal end 305 of the patientcircuit 110 and being delivered to the patient.

The system 300 also provides a second flowpath 319 through the bypasssystem 242. The second flowpath 319 receives gas flowing from the distalend 305 of the patient circuit 110 through the second tube 303 of thepatient circuit and into the second conduit 313 of the bypass system242. The first valve 244 remains closed in the presence of gas flowingin the direction of the second flowpath 319 while the second valve 246is open. As a result, the second flowpath 319 continues through thebridge 315 and out through the first conduit 311 of the bypass system242. The second flowpath 319 delivers gas into the first tube 301 of thepatient circuit 110 where it then passes through the bacterial filter230 and into the ventilator 100. In this second flowpath 319, the gases(e.g., exsufflation gases drawn from the patient during coughassistance) do not pass through the chamber 309 of the humidifier 141.As a result, the risk of liquid from the chamber 309 being passedthrough the first tube 301 of the patient circuit 110 into the bacterialfilter 230 and/or the ventilator 100 is reduced.

FIGS. 4A-4D illustrate various views of an embodiment of the bypasssystem 242 coupled to the chamber 309 of a humidifier. FIG. 4A is aperspective view, FIG. 4B is a partially exploded view, FIG. 4C is aside view, and FIG. 4D is a cross-section taken along line 4D-4D in FIG.4C. Referring to FIGS. 4A-4D together, the bypass system 242 is engagedwith the chamber 309, and the chamber 309 can be configured to becoupled to a standard commercially available humidifier base. Oncecoupled to the humidifier base, liquid within the chamber 309 can beheated. The chamber 309 in the embodiment shown in FIGS. 4A-4D includesa body 401 with a first stem 403 and a second stem 405 projecting awayfrom the body 401. The first conduit 311 of the bypass system 242engages the first stem 403 of the chamber 309, and the first valve 244is within the first conduit 311 such that gas passing through the firstconduit 311 and into the body 401 of the chamber 309 through the firststem 403 must pass through the first valve 244. As described above withrespect to FIG. 3, the first conduit 311 of the bypass system 242connects to the first tube 301 of the patient circuit 110, whichdelivers gases to and from the ventilator 100.

The second conduit 313 of the bypass system 242 couples to the secondstem 405 of the chamber 309. As noted previously, the second conduit 313of the bypass system 242 connects to the second tube 303 of the patientcircuit 110, which connects to the patient connector and delivers gasesto and from the patient. The bridge 315 extends between the firstconduit 311 and the second conduit 313 of the bypass system 242 and thesecond valve 246 is in the bridge 315.

The bypass system 242 can also have a re-filling port 407 coupled to thesecond stem 405 of the chamber 309. The re-filling port 407 can share aportion of tubing with the second conduit 313 such that liquid can beprovided to the chamber 309 through the re-filling port 407. In otherembodiments, the chamber 309 can be filled through a separate port.

FIGS. 5A and 5B illustrate cross-sectional views of another embodimentof a humidifier bypass system 501 in accordance with the presenttechnology. The bypass system 501 can be generally similar to the bypasssystem 242 system illustrated in FIGS. 4A-4D, except that the bypasssystem 501 includes a single controllable valve 503 coupled to acontroller 505 integrated in the control system 174 described above withrespect to FIG. 1. The valve 503 can be moved between a first position(FIG. 5A) and a second position (FIG. 5B) in response to signalsreceived from the controller 505. In the first position (FIG. 5A), thevalve 503 allows inspiration or insufflation gases to pass through thefirst conduit 311, through the first stem 403, and into the chamber 309where the gases are humidified before exiting via the second stem 405and the second conduit 313 to the patient. In the second position (FIG.5B), the valve 503 allows exsufflating gases to pass through the secondconduit 313 across the bridge 315 and out through the first conduit 311without passing through the chamber 309. When the valve 503 is in thesecond position, liquid in the chamber 309 is blocked from flowing backto the ventilator. The single controllable valve 503 therefore providessimilar functionality to the two-valve system described above withrespect to FIGS. 3-4D.

The above detailed descriptions of embodiments of the technology are notintended to be exhaustive or to limit the technology to the preciseforms disclosed above. Although specific embodiments of, and examplesfor, the technology are described above for illustrative purposes,various equivalent modifications are possible within the scope of thetechnology, as those skilled in the relevant art will recognize. Forexample, while steps are presented in a given order, alternativeembodiments may perform steps in a different order. The variousembodiments described herein may also be combined to provide furtherembodiments.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but well-known structures and functions have not been shown or describedin detail to avoid unnecessarily obscuring the description of theembodiments of the technology. Where the context permits, singular orplural terms may also include the plural or singular term, respectively.

Moreover, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the term “comprising” is used throughout to mean including at least therecited feature(s) such that any greater number of the same featureand/or additional types of other features are not precluded. It willalso be appreciated that specific embodiments have been described hereinfor purposes of illustration, but that various modifications may be madewithout deviating from the technology. Further, while advantagesassociated with certain embodiments of the technology have beendescribed in the context of those embodiments, other embodiments mayalso exhibit such advantages, and not all embodiments need necessarilyexhibit such advantages to fall within the scope of the technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

1-21. (canceled)
 22. A system comprising: a cough-assist device having afirst phase configured to provide insufflating gas to a patient circuitand a second phase configured to draw exsufflating gas from the patientcircuit; a humidifier positionable between the cough-assist device and adistal end of the patient circuit, the humidifier comprising a chamberfluidically coupleable to the cough-assist device and/or the patientcircuit and configured to contain water and/or water vapor; and abypass, wherein, when the humidifier is fluidically coupled to thecough-assist device and/or the patient circuit, the bypass is configuredto— route insufflating gas from the cough-assist device to the patientsuch that the insufflating gas is humidified in the chamber, and routeexsufflating gas from the patient circuit toward the cough-assist devicesuch that at least a portion of the exsufflating gas bypasses thechamber.
 23. The system of claim 22 wherein the cough-assist devicecomprises a ventilator configured to provide breathing assistance in afirst mode and cough assistance in a second mode.
 24. The system ofclaim 22 wherein the bypass comprises: a first conduit extending awayfrom the chamber and configured to fluidically couple the cough-assistdevice to the chamber; a second conduit extending away from the chamberand configured to fluidically couple the chamber to the distal end ofthe patient circuit; and a bridge fluidically connecting the firstconduit and the second conduit.
 25. The system of claim 24 wherein thebypass further comprises: a first valve disposed in the first conduit ata position between the chamber and the bridge; and a second valvedisposed in the bridge at a position between the first conduit and thesecond conduit.
 26. The system of claim 25 wherein the first valve is aone-way valve configured to open towards the chamber in the presence ofinsufflating gas, and wherein the second valve is a one-way valveconfigured to open towards the first conduit in the presence ofexsufflating gas.
 27. The system of claim 22 wherein the bypasscomprises: a first valve configured to (a) open in the presence ofinsufflating gas so that insufflating gas from the cough-assist devicepasses through the chamber and (b) close in the presence of exsufflatinggas to prevent exsufflating gas from exiting the chamber; and a secondvalve configured to (c) open in the presence of exsufflating gas fromthe patient circuit so that at least the portion of the exsufflating gaspasses to the cough-assist device without passing through the chamberand (d) to close in the presence of insufflating gas.
 28. The system ofclaim 22 wherein the humidifier is configured to be fluidically coupledto a portion of the patient circuit that receives both insufflating gasand exsufflating gas.
 29. The system of claim 22 wherein the bypass iscoupled to a portion of the patient circuit that receives bothinsufflating gas and exsufflating gas.
 30. The system of claim 22wherein the patient circuit includes a first lumen extending between thebypass and the cough-assist device and a second lumen extending betweenthe bypass and the distal end of the patient circuit, and wherein bothinsufflating gas and exsufflating gas are routed through at least aportion of the first lumen and the second lumen.
 31. A systemcomprising: a cough-assist device having an insufflating moduleconfigured to provide an insufflating gas flow to a patient circuit andan exsufflating module configured to draw an exsufflating gas flow fromthe patient circuit; a humidifier configured to be fluidically coupledto the cough-assist device and the patient circuit, the humidifierhaving a chamber configured to contain water and/or water vapor; and abypass having a first flow path between the cough-assist device and thechamber, a second flow path between the chamber and the patient circuit,and a third flow path between the first and second flow paths, wherein,when the humidifier is fluidically coupled to the cough-assist deviceand the patient circuit, the bypass is configured to— route insufflatinggas through the chamber via the first and second flow paths, and routeat least a portion of the exsufflating gas through the third flow pathsuch that it bypasses the chamber.
 32. The system of claim 31 whereinthe bypass includes a valve system, and wherein the valve system isconfigured to— block the third flow path during insufflation so that theinsufflation gas flow passes through the chamber via the first andsecond flow paths, and open the third flow path and block the first flowpath during exsufflation such that at least the portion of theexsufflation gas flow passes through the third flow path and bypassesthe chamber.
 33. The system of claim 32 wherein the valve systemcomprises: a first passive valve in the first flow path between thechamber and an intersection between the first flow path and the thirdflow path; and a second passive valve in the third flow path.
 34. Thesystem of claim 33 wherein the first passive valve comprises a firstcheck valve configured to open towards the chamber during insufflation,and wherein the second passive valve comprises a second check valveconfigured to open towards the first flow path during exsufflation. 35.The system of claim 31 wherein the humidifier is configured to befluidically coupled to a portion of the patient circuit that receivesboth insufflating gas and exsufflating gas.
 36. The system of claim 31wherein the bypass is coupled to a portion of the patient circuit thatreceives both insufflating gas and exsufflating gas.
 37. The system ofclaim 31 wherein the patient circuit includes a first lumen extendingbetween the bypass and the cough-assist device and a second lumenextending between the bypass and the distal end of the patient circuit,and wherein both insufflating gas and exsufflating gas are routedthrough at least a portion of the first lumen and the second lumen. 38.A humidifier assembly, comprising: a chamber configured to retain liquidtherein; a heater configured to deliver heat to liquid within thechamber; an insufflation flowpath configured to receive insufflating gasfrom a cough-assist device and direct the insufflating gas through thechamber and to a patient circuit when the humidifier assembly isfluidically coupled to the patient circuit; and an exsufflation flowpathconfigured to receive exsufflating gas from the patient circuit anddirect at least a portion of the exsufflating gas to the cough-assistdevice without passing through the chamber when the humidifier assemblyis fluidically coupled to the patient circuit, wherein the humidifierassembly is configured to be fluidically coupled to a portion of thepatient circuit receiving both insufflating gas and exsufflating gas.39. The humidifier assembly of claim 38, further comprising a firstconduit extending away from the chamber and configured to fluidicallycouple the cough-assist device to the chamber; a second conduitextending away from the chamber and configured to fluidically couple thechamber to the patient circuit; and a bridge connecting the firstconduit and the second conduit.
 40. The humidifier assembly of claim 39,further comprising a first valve disposed in the first conduit at aposition between the chamber and the bridge, wherein the insufflationflowpath passes through the first valve, and wherein the exsufflationflowpath does not pass through the first valve.
 41. The humidifierassembly of claim 40, further comprising a second valve disposed in thebridge at a position between the first conduit and the second conduit,wherein the exsufflation flowpath passes through the second valve, andwherein the insufflation flowpath does not pass through the secondvalve.
 42. A method for providing cough assistance to a patient, themethod comprising: delivering insufflating gas from a cough-assistdevice to a patient via a patient circuit having a first conduit, asecond conduit, and a humidifier between the first conduit and thesecond conduit, wherein delivering the insufflating gas comprisespassing the insufflating gas through a chamber in the humidifier,thereby humidifying the insufflating gas before it reaches the patient;and withdrawing exsufflating gas from the patient via the first conduitand the second conduit of the patient circuit, wherein at least aportion of the exsufflating gas bypasses the humidifier.
 43. The methodof claim 42 wherein withdrawing exsufflating gas comprises providing apressure between negative 30-70 cm H₂O in the patient circuit.
 44. Themethod of claim 42 wherein withdrawing the exsufflating gas comprisespassing at least a portion of the exsufflating gas through a bypasscoupled to the humidifier.
 45. The method of claim 43 wherein the bypasscomprises: a first valve configured to (a) open while delivering theinsufflating gas so that the insufflating gas from the cough-assistdevice passes through the chamber in the humidifier and (b) close in thepresence of exsufflating gas to prevent exsufflating gas from exitingthe chamber; and a second valve configured to (a) open while withdrawingthe exsufflating gas from the patient circuit so that at least theportion of the exsufflating gas passes to the cough-assist devicewithout passing through the chamber and (b) to close in the presence ofinsufflating gas.